Because of the intimate association between house cats and humans, one would think that toxo infections from the litter box are commonplace. Actually, most human exposures come from sources unrelated to pet cats. One of them is inadequately cooked meat. Cattle, pigs, and all manner of birds (and especially wild game) can be infected with toxoplasmosis as intermediate hosts. That just means the organism can’t execute a smooth, feline-centric life cycle. Instead, it wanders aimlessly through the host’s body, most often settling in the muscle (meat). Recommended cooking temperatures for the various kinds of meat were established for this exact purpose. Learn how to use a meat thermometer; this skill will keep yielding dividends for the rest of your life.
Another route for toxoplasma exposure is gardening (again, minus basic hand hygiene—which is the amulet against nearly every type of infection). While cysts produced by an indoor cat are removed daily from the immediate environment, the ones deposited by free-roaming cats—in your garden, landscaping, or sandbox—remain there semi-permanently. They have a very, very, very long lifespan. Especially when pregnant or undergoing some sort of immunosuppressive therapy, it is important to wear gardening gloves and wash your hands after taking them off. Always wash your produce before consuming it, even if it was grown organically (i.e., no pesticides). This easy step will help to insulate you against all food-borne illnesses—including toxo.
Now, just one more really important tidbit for the cat lovers. A strictly indoor pet feline, well established in your home, carries an extremely low risk of spreading this parasite; however, certain other kinds of cat could be more of a loose cannon. If you are pregnant or immunosuppressed, it is not the right time for obtaining a new cat from the stray or shelter population, particularly a young one. It is inarguably the worst time of your life to be caring for orphaned kittens. If at all possible, you should keep your pet indoors and prevent him from hunting for mice or birds. Successful hunts end with prey, and that is essentially the same as improperly cooked meat (see above). Hopefully it’s obvious that purchased raw meat diets pose exactly the same threat; these should be avoided if your immune system is impaired in some way.
If you’ve already done those high-risk behaviors, it is still not time to panic. Just make the necessary changes today and consult with your physician so that he or she can guide you with lab testing for yourself. If you’re already taking the safety measures you read about here, then toxoplasma is nothing to worry about.
Dr. M.S. Regan